Air-cooled motor

Abstract

An air passage extending in the axial direction of a motor shaft is formed in a plurality of places in the peripheral wall of a motor housing. An extension tube is fixed to a rear end of the motor housing to provide a space for mounting a rotary joint for connecting a coolant feed pipe to the end of a through hole in the motor shaft, and the extension tube is used as an exhaust (ventilation) passage so that the motor can be cooled with air introduced into the air passage through the tube by using a fan provided on a rear end of the extension tube.

What is claimed is: 
     
       1. An air-cooled motor, comprising: a motor body having a motor shaft in a center thereof,   a motor housing having a plurality of air passages extending in a direction of an axis of the motor shaft;   an extension tube having a first end fixed to one end of said motor housing and an air-cooling fan mounted on a second end of said extension tube, said extension tube forming an internal space between said motor housing and the air-cooling fan allowing at least a rotary joint and piping to be arranged in the internal space, wherein when the air-cooling fan is rotated, outside air is first drawn into the air passages formed in said motor housing and then flows into said extension tube after passing through the air passages, or the outside air is first drawn into said extension tube and then passes through the air passages formed in said motor housing.   
     
     
       2. An air-cooled motor according to claim 1, further comprising: a coolant feed pipe;   a coolant-feeding through hole formed in the motor shaft; and   a connection member, wherein a first end of the coolant feed pipe extends through said extension tube and is connected to an opening end of the through hole in said motor shaft through said connection member.   
     
     
       3. An air-cooled motor according to claim 2, wherein said connection member is arranged between said motor housing and the air-cooling fan. 
     
     
       4. An air-cooled motor according to claim 2, wherein the opening end of the through hole in said motor shaft and at least a part of said connection member are covered with a closed chamber, the closed chamber provided with one of a drain recovering coolant having leaked through said connection member and a gap between said connection member and the through hole in said motor shaft and a drain pipe connected to the drain is arranged to lead to the outside through a peripheral wall portion of said extension tube. 
     
     
       5. An air-cooled motor according to claim 2, further comprising: a housing base having a through hole in a center thereof for passing one end of said motor shaft, said housing base being fixed to one end surface of said motor housing; and   a substantially disc-shaped flinger fixed to a circumference of the one end of the motor shaft so that said flinger is rotated within a closed chamber as the motor shaft rotates, wherein one end surface of said housing base and one end surface of said flinger are arranged to face each other through a slight space provided therebetween to form a rotary seal member between said housing base and said flinger.   
     
     
       6. An air-cooled motor according to claim 4, wherein said connection member is a rotary joint composed of a rotating-side member and a fixed-side member, and the rotating-side member is fitted and fixed to an end of the coolant-feeding through hole in the motor shaft, while the fixed-side member extends through a wall of a closed chamber and is fixed to the wall. 
     
     
       7. An air-cooled motor having a motor shaft and a housing, comprising: a plurality of air passages extending in a direction of an axis of the motor shaft;   an extension tube having a first end fixed to one end of the housing and a fan mounted on a second end of said extension tube, said extension tube forming an internal space between the housing and the fan allowing at least a rotary joint and piping to be arranged in the internal space;   wherein, when the fan is rotated, outside air is first drawn into the air passages formed in the housing and then flows into said extension tube after passing through the air passages, or the outside air is first drawn into said extension tube and then passes through the air passages formed in the housing.   
     
     
       8. An air-cooled motor, comprising: a motor body having a motor shaft formed with a through hole for feeding coolant;   a motor housing formed with a plurality of air passages, each extending in a direction of the motor shaft;   an extension tube having a front end fixed to a rear end of said motor housing;   a duct having a front end fixed to a rear end of said extension tube;   an air-cooling fan housed inside said duct, said air-cooling fan drawing in outside air through the plurality of air passages or sending outside air into the plurality of air passages;   a coolant feeding pipe which goes through a peripheral wall of said extension tube from outside to inside; and   a rotary joint, arranged inside said extension tube, said rotary joint comprising a rotating side member and a fixed side member, the fixed side member being connected to said coolant feeding pipe and the rotating side member rotating together with the motor shaft, wherein coolant fed through said coolant feeding pipe is subsequently fed to the through hole to feed coolant to the motor shaft.